// 易错题
function Person(name, age, sex) {
  var a = 0;
  this.name = name;
  this.age = age;
  this.sex = sex;
  function sss() {
    a++;
    document.write(a);
  }
  this.say = sss;
}
var oPerson = new Person();
oPerson.say();
oPerson.say();
var oPerson1 = new Person();
oPerson1.say();
